[3.15] gh-150258: Show relative percentage on Tachyon flamegraph (GH-150266) (#150312)

[3.15] gh-150258: Show relative percentage on Tachyon flamegraph (GH-150266) (#150312)

gh-150258: Show relative percentage on Tachyon flamegraph (GH-150266)

When running profiling, users rarely care about the global percentage of
the runtime. Often, they want to select a function and measure child
percentages relative to that.

This PR updates the flamegraph tooltips to show both "Percentage" and
"Relative Percentage" when the user clicks a specific function.
(cherry picked from commit fad06746051f6bd95a255d49e38ebf049e965109)

Co-authored-by: Eduardo Villalpando Mello <eduardovil@microsoft.com>